Rocker spring unit

ABSTRACT

A rocker spring unit having a top plate member with laterally projecting tab sections at its side edges for chair attachment and rocker spring seat-forming bosses at its front and rear edges is improved by providing the tab sections with at least one angled edge tapering from a widened reinforcing base therefor and by providing the rear bosses of the top plate member with inward and downward angled seat portions for straight line bottoming of the rocker springs.

O United States Patent 11 1 [111 3,881,713

Joyce May 6, 1975 ROCKER SPRING UNIT 3,547,393 12/1970 Gordin 248/385[75] Inventor: T. Bob Joyce, Mansfield, Ark.

Primary Examiner-Richard A. Schacher Asslgneel P PE ManufaaurmgAssistant ExaminerJeffrey V. Nase Company, Hwkory, Attorney, Agent, orFirm-Richards, Shefte & 22 Filed: May 23, 1973 Pmckfley 21 A l. N 3630321 pp 0 57 ABSTRACT A rocker spring unit having a top plate member with[52] jg b izg i laterally projecting tab sections at its side edges for[51] Int Cl chair attachment and rocker spring seat-forming [58] Fie'ld94 bosses at its front and rear edges is improved by prog f i l vidingthe tab sections with at least one angled edge tapering from a widenedreinforcing base therefor and [56] References Cited by providing therear bosses of the top plate member with inward and downward angled seatportions for UNlTED STATES PATENTS straight line bottoming of the rockersprings. 2,012,575 8/1935 Mclnemey 267/94 2,775,287 12/1956 Mantegna5/351 8 Chums, 5 Drawlng Flgures PATH-HEB um 61975 SHEET 2 OF 2 b2 Fig.5

PRIOR ART BACKGROUND OF THE INVENTION The present invention relates torocker spring units generally and, more particularly, to rocker springunits of the type disclosed in U.S. Pat. Nov 3,547,393. That patentdiscloses a device having top and bottom plate members which arepivotally connected about a centrally disposed horizontal pivot axis atopposed side flanges thereof which are depending and upstanding,respectively. Rocker springs extend between the plate members and areattached thereto at seating bosses disposed at the front and rear edgesof the plate members. Additionally, the top plate member has severallaterally projecting tab sections which are cut out of the side flangesand which have apertures for attachment of the device to the seatportion of a chair structure.

One problem with the unit of U.S. Pat. No. 3,547,393, and with otherunits similar to it, is that the chair attaching tab sections aredifficult to strengthen adequately and tend to fail with a troublesomefrequency. A second problem is that the rocker spring service life isoften shortened objectionably due to eccentric bottoming as a result oftheir common arrangement. The present invention deals with both of theseproblems effectively.

SUMMARY OF THE INVENTION Briefly described, the rocker spring unit ofthe present invention has top and bottom plate members, rocker springsextended between and attached to the plate members, and means allowingthe top plate member to rock relative to the bottom plate member. Thetop plate member has apertured tab sections which project laterally fromits side edge portions and which have at least one angled edge taperingfrom a widened reinforcing base for the tab section. Preferably, the topplate member also has embossed reinforcing ribs extending into the tabsections, most preferably adjacent an angled edge thereof. It is furtherpreferred that the top plate member be rectangularly shaped, have a tabsection adjacent each of its corners, and have embossed ribs extendingbetween the tab sections.

A second embodiment of the present invention has, in addition to any orall of the above features, a top plate member with opposed dependingside flanges, a bottom plate member with opposed upstanding side flangesextending into face-to-face relation to the top plate member sideflanges, means for pivotally connecting the side flanges of the topplate member to those of the bottom plate member at a centrally disposedhorizontal pivot axis, and rocker springs extended between and attachedto the plate members. The plate members have bosses displaced adjacenttheir front and rear edge portions, which form attaching seats for therocker springs, and the bosses adjacent the rear edge portion of the topplate member have downward and inward angled seat portions to providefor straight line bottoming of the rocker springs attached thereto.Preferably, the plate members are rectangularly shaped and a boss islocated closely adjacent each of their corners.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective illustrating arocker spring unit embodying the present invention;

FIG. 2 is a plan view corresponding to FIG. 1;

FIG. 3 is a vertical section taken along line 3-3 of FIG. 1;

FIG. 4 is a sectional illustration of the manner in which rocker springsbottom according to usual prior art practices; and

FIG. 5 is a sectional illustration similar to FIG. 3 but showing therear of the rocker spring unit pivoted downwardly for rocker springbottoming according to the present invention, some parts being removedfrom the drawing for clarity of illustration.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 13 illustrate a device,made according to the present invention, which is generally comprised ofa rectangular top plate member 10, a rectangular bottom plate member 12,front rocker springs 14, rear rocker springs 14', and a swivel base 16.The plate members 10, 12 are aligned vertically and five rocker, springsl4, 14' are attached theretoand extended therebetween, one closelyadjacent each corner of the plate members 10, 12 at the front and rearedge portions 18, 20 thereof and one located rearward of the centers ofthe plate members 10, 12 and approximately equidistant from the sideedge portions 22 thereof. The top plate member '10 has a pair of opposeddepending side flanges 24 which extend into face-to-face relation to apair of opposed upstanding side flanges 26 on the bottom plate member12. The bottom plate member side flanges26 are disposed outward of thetop plate member side flanges 24 and are pivotally connected to the topplate member side flanges 24 by a pair of aligned rivets 28 about acentrally disposed horizontal pivot axis 30 (see FIG. 3). Finally, thebottom plate member 12 is assembled with the swivel base 16 in the usualmanner as noted further below.

The top plate member 10 has four tab sections 32, each located adjacentone corner thereof and laterally projecting from a side edge portion 22thereof. The tab sections 32 are cut out of the side flanges 24 and haveapertures 34 for attachment of the seat portion of a chair structure(not shown). Each of the four tab sections 32 has an angled edge 36which tapers from a reinforcing base 38 at a side edge portion 22 of thetop plate member 10.

As stated above, tab sections such as those described in U.S. Pat. No.3,547,393 are difficult to strengthen adequately. The use of anglededges 36 on the tab sections 32 of the illustrated device provide thetab sections 32 with a widened and substantially stronger reinforcingbase 38. For additional strengthening of the tab sections 32, the topplate member ll) has two embossed ribs 40 which extend diagonallybetween and into the tab sections 32 adjacent the angled edges 36thereof, although it is not necessary that the embossed ribs 40 extendcompletely across the entire width of the top plate member 10, or thatthey be located in any particular relation to the tab sections 32 aslong as they extend into these sections so as to provide the fullstrengthening effect of such ribs.

Both plate members 10, 12 have displaced therein five bosses 42 whichform attaching seats for the rocker springs 14, 14. Two of the bosses 42are located at each front and rear edge portion 18, 20 of the platemembers 10, 12 closely adjacent the corners thereof. The remainingbosses 42 are partially cut out of the plate members 10, 12 and arelocated one on each of the plate members 10, 12 rearward of the centerand approximately equidistant from the side edge portions 22 thereof.Each of the bosses 42 has a raised inwardlyextending portion 44displaced therein which engages and holds the end of the rocker spring14 or 14' which is seated thereat.

According to the present invention, the bosses 42 adjacent the rear edgeportion 20 of the top plate member 10 have inward and downward angledseat portions 46 (see FIG. 3). As stated above, the rear rocker springs48 of a device like that shown in U.S. Pat. No. 3,547,393 (asillustrated in FIG. 4) exhibit eccentric bottoming when the top platemember 50 is tilted backward relative to the bottom plate member 52,thereby causing complicated stressing on the rocker springs 48 whichtends to lessen service life. Straight line bottoming (as illustrated inFIG. 5) and an approximate 50% increase in the useful life of the rockersprings 14 is brought about by providing the top plate member withinclined rear seat portions 46 as described above, which disposes thetop and bottom rear spring seat portions generally parallel when theunit is fully rocked rearward (FIG. 5) until the springs are fullycompressed, with the result that the spring coils are in substantiallyfull contact throughout rather than contacting only at the rearmostedges as in the prior art devices.

The required degree of inclination of the seat portions 46 depends uponthe distance from the pivot axis to the seat portions, the space betweenthe plate members l2 and 10 in a neutral position, and the bottomingoutor fully compressed height of the springs 48. In the embodiment shown inFIGS. 1-3, which incorporates a design adopted for actual use, thedegree of inclination of the seat portions 46 from the plane of the topplate member 10 is approximately 10.

Although in the illustrated embodiment only the rearmost two spring seatportions are inclined, it should be understood that other of the springseat portions can be similarly inclined, as for example the centerspring seat portion that is adjacent the rear edge of the top platemember 10.

The bottom plate member 12 has a large, centrally located aperture (notshown) for attachment by a central staking rivet (not shown) to theswivel base 16 and is arranged for swivel mounting about the centralstaking rivet by complementary grooves (not shown) concentrically formedin the lower face of the bottom plate member 12 and in the upper face ofthe swivel base 16 to contain bearing balls (not shown) that support theswiveling action in the manner described in the abovementioned U.S. Pat.No. 3,547,393.

The present invention has been described in detail above for purposes ofillustration only and is not intended to be limited by this descriptionor otherwise to exclude any variation or equivalent arrangement thatwould be apparent from, or reasonably suggested by,

the foregoing disclosure to the skill of the art.

I claim:

1. In a rocker spring unit comprising a top plate member having opposeddepending side flanges, a bottom plate member having opposed upstandingside flanges extending into face-to-face relation to said top platemember side flanges, means pivotally connecting said top plate memberside flanges to said bottom plate member side flanges at a centrallydisposed horizontal pivot axis, rocker springs extended between andattached to said plate members, and bosses displaced in said platemembers adjacent front and rear edge portions thereof to form attachingseats for said rocker springs, the improvement which comprises angledseat portions in said bosses adjacent said rear edge portion of said topplate member, said seat portions being angled downwardly and forwardlyfor straight line bottoming of the rocker springs attached thereto upondownward rocking of said top plate member rear edge portion.

2. A rocker spring unit as defined in claim 1 and further characterizedin that said downwardly and forwardly angled seat portions are disposedto be generally parallel with the corresponding bottom plate seatportions when the rocker springs therebetween are fully compressed.

3. A rocker spring unit as defined in claim 1 and further characterizedin that said downwardly and forwardly angled seat portions are inclinedapproximately 10 degrees from the plane of said top plate member.

4. A rocker spring unit as defined in claim 1 and further characterizedin that said plate members are rectangularly shaped and a boss islocated closely adjacent each comer of said plate members.

5. A rocker spring unit as defined in claim 1 and further characterizedin that said top plate member has apertured tab sections laterallyprojecting from side edge portions thereof for attachment of said unitto the seat portion of a chair structure, said tab sections having atleast one angled edge for tapering of said sections from a widenedreinforcing base.

6. A rocker spring unit as defined in claim 5 and further characterizedin that said top plate member has embossed ribs extending into saidwidened reinforcing bases of said tab sections for additionalreinforcement thereof.

7. A rocker spring unit as defined in claim 6 and further characterizedin that said embossed ribs extend into said tab sections adjacent anangled edge thereof.

8. A rocker spring unit as defined in claim 7 and further characterizedin that said top plate member is rectangularly shaped; in that said topplate member has a tab section located adjacent each corner of said topplate member; and in that said embossed ribs extend between said tabsections.

1. In a rocker spring unit comprising a top plate member having opposeddepending side flanges, a bottom plate member having opposed upstandingside flanges extending into face-to-face relation to said top platemember side flanges, means pivotally connecting said top plate memberside flanges to said bottom plate member side flanges at a centrallydisposed horizontal pivot axis, rocker springs extended between andattached to said plate members, and bosses displaced in said platemembers adjacent front and rear edge portions thereof to form attachingseats for said rocker springs, the improvement which comprises angledseat portions in said bosses adjacent said rear edge portion of said topplate member, said seat portions being angled downwardly and forwardlyfor straight line bottoming of the rocker springs attached thereto upondownward rocking of said top plate member rear edge portion.
 2. A rockerspring unit as defined in claim 1 and further characterized in that saiddownwardly and forwardly angled seat portions are disposed to begenerally parallel with the corresponding bottom plate seat portionswhen the rocker springs therebetween are fully compressed.
 3. A rockerspring unit as defined in claim 1 and further characterized in that saiddownwardly and forwardly angled seat portions are inclined approximately10* degrees from the plane of said top plate member.
 4. A rocker sprIngunit as defined in claim 1 and further characterized in that said platemembers are rectangularly shaped and a boss is located closely adjacenteach corner of said plate members.
 5. A rocker spring unit as defined inclaim 1 and further characterized in that said top plate member hasapertured tab sections laterally projecting from side edge portionsthereof for attachment of said unit to the seat portion of a chairstructure, said tab sections having at least one angled edge fortapering of said sections from a widened reinforcing base.
 6. A rockerspring unit as defined in claim 5 and further characterized in that saidtop plate member has embossed ribs extending into said widenedreinforcing bases of said tab sections for additional reinforcementthereof.
 7. A rocker spring unit as defined in claim 6 and furthercharacterized in that said embossed ribs extend into said tab sectionsadjacent an angled edge thereof.
 8. A rocker spring unit as defined inclaim 7 and further characterized in that said top plate member isrectangularly shaped; in that said top plate member has a tab sectionlocated adjacent each corner of said top plate member; and in that saidembossed ribs extend between said tab sections.